let n = 7
let count = n
let result = 0
// 求n的阶层
for (let i = n - 1; i > 0; i--) {
  count = count * i
}
//console.log(count)
// n的阶层的十进制有几个0
let arrNum = Array.from(String(count))
//console.log(arrNum)
for (let i = 0; i < arrNum.length; i++) {
  if (arrNum[i] === '0') {
    result++
  }
}
console.log(result)
